Hi guys I am really looking for some hand here with this ABS issue of mine. I bought the car recently from private owner and wasn't hoping to go through this. I have already shown the issue in 2 different garages without any success.

ABS appears in the dashboard after driving it for a while ( I believe it's to do with heat). The diagnostic located electrical fault in left rear wheel. So the garage ordered a new sensor, this didn't work either. All 4 sensors are reading same speed. The mechanic swapped left and right wheel rims, the problem was still in the left wheel. Now though, from electrical fault it's gone to implausible signal. The garage hasn't yet checked the wiring and the pump. Since the warning is intermittent he had trouble finding the issue and suggested that I bring the car once it develops permanent damage. If anyone has had this issue before please help a brother out. One more thing I have noticed is during hot weather the sign appears much quicker. The car was parked under sunlight for good few hours and the moment I drove out of the driveway ABS came up. Same day I took it for drive during somewhat chilly evening no sign of it for almost half an hour. Thank you!

Could be the hub on rear left wheel if the sensor did not fix it.

 

Heat should play no part in it, it came on as you drove out the drive because the ECU did not get the correct signal from the wheel sensor, which as mentioned if it is new, then could be hub

 

Any play in the left rear wheel bearing ?

 

Edited 8 September, 20196 yr by UrbanPanzer

Implausible signal would lend itself to a bearing. 

I had recent ABS fault and mine too, showed left hand rear.Came on now and again. Brake pads were low so changed them but was unhappy with braking system so took it for new fluid. The fluid in the reservoir was starting to blacken and the repairer thought the master cylinder was worn so replaced that. New fluid and master cylinder and since then, no ABS issue, even after testing by doing emergency stops.

 

My advice is get fluid level checked and/or changed if needed and get brake pads/discs checked/changed if needed. 

If they are ok then fine but if low or worn, they need doing anyway so its a good starting point.

The seals in the master cylinder wear and can fail and according to Skoda, cannot be replaced but the fitter said its quicker to fit a new one anyway. Of course, yours could be fine but start with the brakes, check fluid, check when last replaced, etc.

Edited 9 September, 20196 yr by mrgf

19 minutes ago, mrgf said:

 the repairer thought the master cylinder was worn so replaced that

 

What was the diagnosis based on? Anything tangible? I've never known a Fabia master cylinder to wear out before.

Thank you guys for your replies. As for the bad bearing I haven't heard any noise or seen any symptoms in that wheel. The mechanic did swap the left and right wheel hubs to see if the problem would move to another place. But it still remained in the rear left wheel. I will get in touch with the mechanic and discuss these ideas.

 

In the meantime what are some of the issues we can rule out in my situation. From what I see it doesn't seem like there's a electric fault between the pump and the sensor since it's picking up the speed. Sensor seems to be fine as well since all of them are of same speed. 

 

Anyways I will keep you guys up-to-date of the situation. Thanks for the help everyone.

On 08/09/2019 at 21:52, UrbanPanzer said:

Could be the hub on rear left wheel if the sensor did not fix it.

 

Heat should play no part in it, it came on as you drove out the drive because the ECU did not get the correct signal from the wheel sensor, which as mentioned if it is new, then could be hub

 

Any play in the left rear wheel bearing ?

 

I went to the mechanics today and had a chat about the issue again. Couldn't plug in the diagnostic system as it was updating. Anyways the wheel bearing seems to be in a good condition. It hasn't showed any symptoms at all no noise or any unwanted movement of the wheel. As for the hub itself the mechanic had swapped rear left and rear right hubs to see if the problem would move to different location. Unfortunately it was still in the same place. At that point however, the fault code went from electrical fault in the circuit to implausible signal. 

On 09/09/2019 at 15:03, mrgf said:

I had recent ABS fault and mine too, showed left hand rear.Came on now and again. Brake pads were low so changed them but was unhappy with braking system so took it for new fluid. The fluid in the reservoir was starting to blacken and the repairer thought the master cylinder was worn so replaced that. New fluid and master cylinder and since then, no ABS issue, even after testing by doing emergency stops.

 

My advice is get fluid level checked and/or changed if needed and get brake pads/discs checked/changed if needed. 

If they are ok then fine but if low or worn, they need doing anyway so its a good starting point.

The seals in the master cylinder wear and can fail and according to Skoda, cannot be replaced but the fitter said its quicker to fit a new one anyway. Of course, yours could be fine but start with the brakes, check fluid, check when last replaced, etc.

Mrgf thanks for the advice. I checked the brake fluid today. The level is just fine also the fluid seems to be in good state. Its all nice and clear. I haven't checked the brakes yet though since its a drum brake system and I didn't have the right tool to open the hub. I took the car out for drive earlier and was able to slam the brakes fully a few times, didn't get any bad vibes off the brakes. To be honest I was hoping for the ABS light to pop on, it didn't happen. It just comes out of no where after driving for a while. 

On 08/09/2019 at 21:59, Tech1e said:

Implausible signal would lend itself to a bearing. 

Hi Tech1e, was having a chat with the mechanic earlier about a bad wheel bearing but he seems to rule out that issue. No other symptoms of bad bearing. You see the fault code used to be electrical fault after swapping the hub it became implausible signal. That's why he had asked me to came back in couple of days to see whether or not the fault code would change. Unfortunately he was updating his software so couldn't do it. He says the abs ring is in good state too. 

I had a chance to open the rear left wheel where the abs issue is. I found that the hub isn't spinning freely and is slightly jammed. I have attached a video link to the footage. As I mentioned previously the abs issue comes on after driving for a while. Could this be the reason for it. Can someone please look into it? Thanks very much. 

 

I honestly don't think that "would" set the ABS off, often drum brakes will do that...........but offcourse it's possible....

 

Have you checked the wheel bearing yourself ?? (obviously with the wheel fitted and off the floor)

On 09/09/2019 at 15:23, Tech1e said:

 

What was the diagnosis based on? Anything tangible? I've never known a Fabia master cylinder to wear out before.

It was based on dirty fluid coming back in to the cylinder. The braking was too soft with the pedal needing to be fully depressed and it only slowing the car, when usually a light press would slow to a stop quite easily. I expected slightly less power to the brakes for a while, with the new discs and pads but it was like driving an old moped, in the wet! The fluid was changed, no improvement and the cylinder replaced, all working well.

I think you would call that "Tangible". Seals were suspected to be worn. TBH, the car has done 140,000M as a tuition vehicle so not a shock to the system for it to be worn out. Still no ABS light, either since then. The original thing being done was pads and discs, by myself.

Just to update on this one. I got the ABS issue resolved. Had to bring it to the showroom where they changed the wheel bearing and the abs sensor straight away. Unfortunately the other garages couldn't do it even with my suggestion about the wheel bearing, thanks to @Tech1e. Ah well it was one expensive fix but it's done now. Thanks everyone for the responses.